Field of the Invention
The present invention relates to an installation structure for a canister that adsorbs an evaporative gas within a fuel tank.
Description of the Related Art
In automobiles (motor vehicles), an evaporative gas of fuel within a fuel tank is adsorbed using a canister and the adsorbed evaporative gas is desorbed from the canister and treated so that the evaporative gas in the fuel tank may not be released into the atmosphere.
The adsorption and desorption efficiency of the canister increases with increase in the canister temperature. Usually, therefore, the canister is arranged inside an engine compartment where the interior temperature is high. However, there is a tendency for more and more evaporative gas to be treated, and it is often the case that the capacity of the canister has to be increased correspondingly. In such a case, it is difficult to install the canister inside the engine compartment because of its limited space.
Thus, in many cases, the canister is installed at the rear part of a vehicle body where the space for installation is easily available. Recently, attempts have been made to raise the temperature of the canister by utilizing the structure of the rear part of the vehicle body. For example, the canister is arranged in the space surrounded by a side member, a cross member and an exhaust pipe located at the rear part of the vehicle body, as disclosed in Japanese Patent No. 2910607, or the canister is arranged in the vicinity of a differential gear unit, as disclosed in Japanese Patent 5101686, with a view to raising the temperature of the space in which the canister is arranged.
In the case of the former structure, however, the space in which the canister is arranged is large, and also since the underside of the canister is left open, the temperature of the canister does not rise satisfactorily. The latter structure relies upon the heat from the differential gear unit (i.e., heat from the oil in the differential gear unit), so that the canister temperature does not rise satisfactorily.